For the last few days, I’ve been watching the new Game of Thrones trailer on repeat. Before that, it was the spot for Pirates of the Caribbean: Dead Men Tell No Tales. And there was a good amount of time a few years back when I played the third Force Awakens trailer for hours on end.

None of this is because I felt the need to see Cersei puffing out a breath of frigid air over and over again, or because watching Johnny Depp phone in another cash-grab performance as Jack Sparrow will somehow improve based upon the number of repeat viewings. No, I watch trailers on loop for the music — which is often created exclusively for use in these bits of preview footage, never making its way to the finished film or show, or even a dialogue-free release.

That’s because most films and shows don’t actually own the music used in trailers. There are whole production companies that specialize exclusively in producing music that studios then license in lieu of a finished score. It’s makes sense if you think about it — the actual score for a movie tends to be developed alongside or even after the film is completed, well after the promotional campaign for any film has begun. But film companies still need something to put in as backing music. Trailer music, which is composed specifically to complement specific genres or themes, is usually far cheaper to license than a popular song like “Bohemian Rhapsody.”

But since they’re either written exclusively for a specific trailer or licensed by studios from a general catalog, many trailer songs never see the light of day. The aforementioned Game of Thrones trailer, for example, features a remixed version of the song “Sit Down” by the band James that I find far preferable to the original. That cover only exists in its abridged form found in the clip. Or the final Beauty and the Beast trailer, which features a stunning orchestral version of the title song performed by John Legend and Ariana Grande, is nowhere to be found on the soundtrack.

Since it’s licensed and is meant to fade into the background, trailer music is often misattributed. For example, that Force Awakens trailer — with its haunting, dramatic version of some classic Star Wars themes — was, per a Slashfilm report, composed by Frederick Lloyd and John Samuel Hanson, not famed series composer John Williams. That’s also likely why that track never received a full release, or why that bolder sound is wholly missing from the more pedestrian soundtrack that Williams delivered.

Or consider the music of the second Inception trailer, which originated the famous “Inception horns.” That sound effect, which was aped by dozens of other trailers, is an original composition called “Mind Heist“ by composer Zack Hemsey, not Hans Zimmer, who scored the actual film.

Still, there is hope. While many of the these songs will remain in the background of trailers forever, some of the more popular trailer companies like Two Steps from Hell, Audiomachine, and Really Slow Motion have in recent years taken to releasing album compilations of their compositions to the general public. And even if I never get a studio version of the “Sit Down” cover or the booming version of the Pirates of the Caribbean theme, I can at least take solace in the fact that the trailers where the songs come from aren’t going anywhere.